The Superconducting Radio-Frequency Linear Accelerator Components for the European Spallation Source: First Test Results

The European Spallation Source requires a pulsed linac with an average beam power on the target of 5 MW, which is about five times higher than the most powerful spallation source in operation today. Over 97 % of the acceleration occurs in superconducting cavities. ESS will be the first accelerator to employ double spoke cavities to accelerate beam. Accelerating gradients of 9 MV/meter is required in the spoke section. The spoke section will be followed by 36 elliptical 704 MHz cavities with a geometrical E of 0.67 and elliptical 704 MHz cavities with a geometrical E of 0.86. Accelerating gradients of 16.7 and 20 MV/m are required in the medium and high-E elliptical cavities, respectively. Initial gradient test results will be presented in which results exceed expected requirements. (Less)